.\" Copyright (c) 2015 William Woodruff (william@tuffbizz.com)
.\"
.\" SPDX-License-Identifier: Linux-man-pages-copyleft
.\"
.TH get_phys_pages 3 2024-06-15 "Linux man-pages 6.9.1"
.SH NAME
get_phys_pages, get_avphys_pages \- get total and available physical
page counts
.SH LIBRARY
Standard C library
.RI ( libc ", " \-lc )
.SH SYNOPSIS
.nf
.B "#include <sys/sysinfo.h>"
.P
.B long get_phys_pages(void);
.B long get_avphys_pages(void);
.fi
.SH DESCRIPTION
The function
.BR get_phys_pages ()
returns the total number of physical pages of memory available on the system.
.P
The function
.BR get_avphys_pages ()
returns the number of currently available physical pages of memory on the
system.
.SH RETURN VALUE
On success,
these functions return a nonnegative value as given in DESCRIPTION.
On failure, they return \-1 and set
.I errno
to indicate the error.
.SH ERRORS
.TP
.B ENOSYS
The system could not provide the required information
(possibly because the
.I /proc
filesystem was not mounted).
.SH STANDARDS
GNU.
.SH HISTORY
Before glibc 2.23,
these functions obtained the required information by scanning the
.I MemTotal
and
.I MemFree
fields of
.IR /proc/meminfo .
Since glibc 2.23,
these functions obtain the required information by calling
.BR sysinfo (2).
.SH NOTES
The following
.BR sysconf (3)
calls provide a portable means of obtaining the same information as the
functions described on this page.
.P
.in +4n
.EX
total_pages = sysconf(_SC_PHYS_PAGES);    /* total pages */
avl_pages = sysconf(_SC_AVPHYS_PAGES);    /* available pages */
.EE
.in
.SH EXAMPLES
The following example shows how
.BR get_phys_pages ()
and
.BR get_avphys_pages ()
can be used.
.P
.\" SRC BEGIN (get_phys_pages.c)
.EX
#include <stdio.h>
#include <stdlib.h>
#include <sys/sysinfo.h>
\&
int
main(void)
{
    printf("This system has %ld pages of physical memory and "
            "%ld pages of physical memory available.\[rs]n",
            get_phys_pages(), get_avphys_pages());
    exit(EXIT_SUCCESS);
}
.EE
.\" SRC END
.SH SEE ALSO
.BR sysconf (3)
